Gear.



WITNESSES J.KENNEDY.

GEAR.

APPLICATION FILED OCT. 14, I914.

Patented June 22, 1915.

2 SHEETS-SHEET I. I

INVENTOR NVVL Cuba J. KENNEDY.

GEAR.

APPLICATION FILED OCT. 14. IBM.

1, 1 44, 1 3,, Patented June 22, 1915,.

2 SHEETSSHEET 2- WITNESS rr INVENTOR MMMWA JULIAN KENNEDY, OFPITTSBURGH, PENN SYLVANIA.

GEAR.

specificatioii of Letters Patent.

Patented, June 22, 1915.

Application filed October 14, 1914. Serial No. 866,621.

.To all whom "it may concern:

Be it known that I, JULIAN KENNEDY, a citizen of the United States,residing at Pittsburgh, in the county of Allegheny and State ofPennsylyania, have invented a new and useful Improvement in Gears, ofwhich the followingis a full, clear, and exact de-- scription, referencebeinghad to the accompanying drawings, forming part of thisspecification, in which- Figure 1 isa view partly in side elevation andpartly in section of adouble helical gear, illustrating my invention,Fig. 2 is an end view of one of the gear rin'gs, looking at theinner-end thereof, Fig. 3 is a side view of the gear rings removed.Figs. and 5 are fragmentary sectional views showing two different formsof screw threads which may be employed. Figs. 6 and 7 are longitudinalsectional views showing a modification. Fig. 8-is a section on the lineVII- VII of Fig. 7. Figs. 9 and 10 are longitudinal sectional viewsshowing other embodiments'of my invention. Fig. 11is a view partly insection and partly in side elevation, showing still another embodimentof the invention. 4

My invention has relation to improvements in gears; and is particularlyapplicable to large gears such, for instance, as are employed in rollingmill drives, althoughusefulfor various other pur oses.

, The invention is also especially applicable to double helical, orherring-bone gears.

;In the manufacture of large gears, if the ,rim portion of the gearcarrying the gear teeth is formed integral with the bodyof the gear orwith the shaft member which car'- .ries' it, it is difiicult to properlytemper metal owing to the relatively large mass.-.

If, on the other hand, the rim portions of the ears are made separatelyand are. fastoned to the shaft or carrier after being tempered accordingto the usual methods, there is danger that they :may become warped ortwisted; and when keys are used to secure them to the body or carrier,the

cutting of the key-ways not only weakens the'gears, but the driving ofthekeys may start cracks or initial fracture-points. My invention isdesigned to provide means whereby these difliculties may be overcome andthe rim portions of-the gears may be separately formed and readilysecured to the shaft or carrier ina secure manner,

without distorting or lweakening them in any way.

Referring first to that form of my invention which is shown in Figs. 1to 4,. inclusive, the numeral 2 designates a shaft membercarryingadouble helical or herringbone gear. This gear is formed in two separaterings orrim p'ortions3 and 4;. and to secure them in place theshaftmember 2 is formed with right and left hand threaded portions 5 and 6.These two threaded ortions' are separated from each other at t eiradjacent ends by a clearance space 7 I In making the gear, the ring orrim mem-" bers 3 and 4 may have their gear teeth separately cut therein.They are then screwed upon the right and left hand threaded portionsfrom opposite ends, until the gear teeth properly aline. They can thenbe marked and screwed away from each other sufficiently to permit of thedrilling of registering seats fora number of dowel pins 8.

- The dowels are then inserted and the members are again screwed uptogether, the

dowels locking the two members together with the gears in correctlynegisteringrelation. During this. operation, as soon as the dowels areinserted in both gear members,

the latter are turned inunison until they come into the final positionsshown. In service, it will be readily seenthat the tendency is toconstantly tighten the ring or rim members on their threaded connectionswith the shaft, since the two members. are connected as a unit by thedowels so far as any relative turning movement is concerned. The

screw threads 5- and 6. may be of the standard V-form shown in Figs. '1and 4; or they may be of the modified formshownat 5 -and 6 in Fig. 5, inwhich each tooth has one relatively long sloping. face and its otherface is relativel shorter and more abrupt.

In either form, the intermeshing threads of the shaft and gear membersmay'be given what better adaptedfor use where it may be desired toremove or renew the ring or rim '8, the two gear members 12 and 13 areIVhen it is desired to remove either gear member, this ring or separatorcan be cut out to permit the gear members to be unscrewed from theshaft. 5

In the construction shown in Figs. 7 and screwed on to the shaft 14 inthe same manner as in the constructions above described,

but each of them is formed at its outer end with an inturned flange 15.Each of these flanges is formed with a, plurality of half circularrecesses 16, which register with corresponding half recesses 17 in theshoulders 18 of the 'shaft.- These registering recesses form seats forpins 19 which act to secure the gear members to the shaft.

Fig. 9 shows an embodiment of my invention in which the shaft or carrier20 is itself, rovided with one set of gear teeth 21 and a so has athreaded portion 22 upon which is secured a gear rim or ring 23 havinggear teeth 24. The direction of the threads forming the connection forthemember 23 is such that the load or strain on said members tends totighten the connection.

Fig. 10 shows a form of my invention in which the shaft member 25 hastwo threaded portions 26 and 27 having screwed thereon, respectively,the gears 28 and 29. .The threads forming the connection for the twogears are of the same hand; and it will be ber 2 is formed at one endwith a projection 2 of such form or character that it will not permitone of the gear-rings or rims to be screwed on over that end ofthe'shaft.

In such cases, I provide the shaft with a,

screw threaded portion 30 with the threads running in one direction andof relatively large diameter, and an adjacent screw threaded portion. ofsmaller diameter with a reverse thread. The two gear members 32 and 33can be screwed in place from the same end. While I- have shown thethreads of the portions 30 and 31 cut directly on the vides a secure 1'ency in service is to constantly tlghten the body of the shaft, this isnot essential as they may be formed on any suitable carrier.

The advantages of my invention will be readily understood, since itentirely obvlates the employment of keys or other fastenings having aten cy to strain or fracture the gears, or to we k loose in service; andprofastening in which the tendconnection between the gear members andthe shaft on'carrier. The invention alsoovercomes th difficulties ofimproper alinement of the gearteeth. My invention also provides a gearin which the rim portion can be formed of one grade of'metal of properdegree of hardness and wear resisting qualiadjacent oppositely threadedportions and two separate rim or ring members screwed on said threadedportions, and having teeth which together form they complete gear;substantially as described.

- 2. A'double helical or herring-bone gear, comprising a body portion orcarrier having adjacent oppositely threaded portions and 'two separaterim orv ring members screwed on said threaded portions, and having teethwhich together form the complete gear, together with means for securingthe two rim or ring members against independent tuming movement'on thebody or carrier; substantially as described.

3. A double helical or herring-bone gear,

comprising a shaft member or carrier having adjacent right .and leftthreaded portions separated from each other by a clearance space and twoseparate gear members screwed on said threaded portions, and havingmeans for locking them together to prevent independent turning thereofon the shaft or carrier; substantially as described.

4. A gear of the character described, comprising a shaft or carriermember having adjacent right and left threaded portions and two separatetoothed rin or rim membersscrewed on said threade portions, and havinginterposed connecting means; substantially as described. 1

' In testimony whereof, I have hereunto set my hand.

JULIAN KENNEDY. Witnesses:

H. W. RAUO, J. W. KENNEDY.

